This invention relates to upholstered seats consisting of an in situ foam core based on a cold foam formulation and of a covering which may contain more than one layer and to a process for producing an upholstered seat with improved standards of comfort by back foaming the covering material in a mold.
In upholstered seats, the foam core and the seat covering (seat cover) are often produced in separate operations, the seat cover subsequently being fastened to the back of the cushion or to the cushion support. Sewing the seat cover and covering the foam core are expensive and labor-intensive operations.
German Pat. No. 2,227,143 describes a directly back-foamed upholstered seat consisting of a textile covering with a sealing layer and an in situ foam core. The sealing layer is impermeable to foam and air. To produce a directly back-foamed upholstered seat such as this, a covering backed by an elastic, sealing film is introduced into a vacuum forming mold, deep drawn and the empty space filled with foam. Deep drawing is necessary both for fixing the covering and for forming the exact contour of the upholstered seat. One of the disadvantages of upholstered seats of this type lies in the fact that the dissipation of heat and moisture is prevented by the air-impermeable film. As a result, the temperature of the seat when it is in use very quickly approaches body temperature, which is uncomfortable for the person sitting on the seat.
Hitherto, positioning of the covering material in the mold used for in situ back foaming has been achieved by applying a vacuum to an air-impermeable covering material, so that the covering readily developed creases, accompanied by poorly developed contours. In particular, difficulties were involved in exactly aligning a patterned covering material. Typical of such processes are those in U.S. Pat. Nos. 3,258,511, 3,431,331 and 3,932,252.